Drift measurement system

ABSTRACT

A drift measurement system to quantitatively measure the drift emitted from a cooling tower. The drift measurement system includes: sample collecting means for collecting test samples from various points in the fan stack exhaust air; isokinetic sampling control means to insure that the drift particles collected are truly representative of those entrained in the exhaust air; cyclone separator means for separating the liquid or solid particles from the test sample; and container means for receiving the separated liquid or solid particles.

United StatesPatent n91 Ovard [54] DRIFT MEASUREMENT SYSTEM [75]Inventor: John C. Ovard, Santa Rosa, Calif.

[73] Assignee: Ecodyne Corporation, Chicago, Ill.

[22] Filed: Mar. 17, 1972 [21] Appl. No.: 235,484

[52] US. Cl. 73/28, 73/421.5 A [51] Int. Cl. G01n 1/22 [58] Field ofSearch 73/28, 421.5 A

[56] References Cited UNITED STATES PATENTS 2,353,828 7/1944 Hydem 73/28X FOREIGN PATENTS OR APPLICATIONS Great Britain 73/4215 A Dec. 25, 1973Primary ExaminerJerry W. Myracle AttorneyCharles M. Kaplan et al.

[5 7 ABSTRACT A drift measurement system to quantitatively measure thedrift emitted from a cooling tower. The drift measurement systemincludes: sample collecting means for collecting test samples fromvarious points in the fan stack exhaust air; isokinetic sampling controlmeans to insure that the drift particles collected are trulyrepresentative of those entrained in the exhaust air; cyclone separatormeans for separating the liquid or solid particles from the test sample;and container means for receiving the separated liquid or solidparticles.

11 Claims, 5 Drawing Figures PATENTEU was I915 3; 780,567

SHEET 10$ 2 1 DRIFT MEASUREMENT SYSTEM BACKGROUND OF THE INVENTION Thisinvention relates to a method for and a drift measurement system toquantitatively measure the drift emitted from a cooling tower.

Cooling tower drift has been traditionally defined as mechanicallyentrained droplets which are carried along with the air passing througha cooling tower and exhausted to the environment. Based on thisdefinition, one would expect these water particles to have essentiallythe same chemical composition as the circulating water in the coolingtower. However, the basic evaporative process in a cooling tower resultsin airborne solid salt particles since smaller droplets evaporatecompletely. Thus, solid particles or water particles with saltconcentrations higher than the composition of the circulating water arealso exhausted to the atmosphere. These particles cannot be overlookedin evaluating drift and its environmental effects since they are alsopotentially detrimental to the environment. This is particularlyimportant with the advent of salt or brackish water cooling towersbecause of recent attention focused on drift as a potential danger tolocal vegetation or as an air pollutant. Experiences with cooling towerscurrently operating with salt water indicate that problems of thisnature do not occur. However, due to a lack of quantitative informationon drift levels and the expected use of much larger salt water coolingtower units than are currently operating, definitive proof is essential.

Several techniques have been developed for the discriminate measurementof small airborne water particle size and quantities in the range ofthose encoun tered in cooling tower drift. Most of these methods haveevolved from meterological investigations on clouds, fog andprecipitation. The two major problems inherent in such techniques arethe difficulty of collecting a representative sample and the maintenanceof the droplet size long enough for measurement. One method, which ispotentially applicable to cooling tower drift measurement work, usesglass slides coated with a material which preserves the impression waterparticles make on impact with the slide. The impressions can be examinedlater under a microscope to determine their size. For this technique togive accurate results, the relationship between the impression on aslide coating must be correlated with the impacting water particle size.Another technique developed to determine particle size bases itsparticle measurement ability on diffraction rings orcoronas producedwhen high intensity light is scattered while passing through waterdroplets entrained in the air. This method has limited application sincedifficulties are encountered when trying to measure particles withdiameters smaller than 50 to 60 microns because of the very smallRaleigh scattering range.

All of the above techniques, while having the advantage of discriminatemeasurement of particle size, have two serious limitations when appliedto the field measurement of cooling tower drift. Firstly, the samplingtimes with these methods are necessarily extremely short; usually in therange of a few seconds or fractions of a second depending on the method.To obtain a truly representative measurement of cooling tower driftrequires that a large number of samples be analyzed to reflect a truestatistical average of particle size and SUMMARY OF THE INVENTION Themethod and apparatus of the present invention overcomes theselimitations since it does not measure particle size, but extracts acontinuous isokinetic sample from the cooling tower exhaust air alongwith the associated drift particles.

It is a primary object of the present invention to provide a method andapparatus for quantitatively measuring the drift emitted from a coolingtower.

Another object is to provide a method and apparatus for accuratelycollecting a drift sample which represents the total average driftemitted from a cooling tower.

A further object of the invention is to provide a method and apparatusfor quantitatively measuring the drift emitted from a cooling towerwhich permits chem; ical analysis to determine the dissolved solidcontent of the drift.

Still another object is to provide a drift measurement system formeasuring the drift emitted from a cooling tower which can be moved tocollect samples from various parts of the fan stack and is adaptable tomost sizes of cooling tower fan stacks.

The drift measurement system of the present invention includes: samplecollecting means for collecting test samples from various points in thefan stack exhaust air; isokinetic sampling control means to insure thatthe drift particles collected are truly representative of thoseentrained in the exhaust air; cyclone separator means for separating theliquid or solid particles from the test sample; and container means forreceiving the separated liquid or solid particles. Mono-rail means arereleasably secured to the fan stack to support and guide the samplecollecting means and thereby permit same to be positioned to collectsamples at pre-selected locations in the exhaust air.

BRIEF DESCRIPTION OF THE DRAWINGS Other objects and many of theattendant advantages of this invention will be readily appreciated asthe same becomes better understood by reference to the followingdetailed description when considered in connection with the accompanyingdrawings, in which like reference numerals designate like partsthroughout the figures thereof and wherein:

FIG. 1 is a perspective view of a typical cooling tower fan stackequipped with the drift measurement system of the present invention;

FIG. 2 is a schematic representation of the drift measurement system ofFIG. 1;

FIG. 3 is an enlarged perspective view of the sample collectingapparatus of the drift measurement system of FIG. 1;

FIG. 4 is an elevational view of the collecting jar; and FIG. 5 is anenlarged perspective view of the control apparatus of the driftmeasurement system of FIG. 1.

DESCRIPTION OF A PREFERRED EMBODIMENT Referring to FIG. 1, a coolingtower fan stack is shown having a drift measurement system of thepresent invention secured to the upper rim thereof. Drift measurementsystem 20 includes sample collection apparatus 30, isokinetic controlapparatus 40, and mono-rail apparatus 50. Sample collection apparatus 30traverses the fan stack discharge on mono-rail apparatus 50 and extractsrepresentative samples from various positions in the plane of the fanstack discharge. Control apparatus 30 insures that the extracted sampleof drift particles are truly representative of those entrained in theexhaust air at the sampling point.

Referring to FIG. 2, a schematic representation of sample collectionapparatus 30 and isokinetic control apparatus 40 are shown as includinga sample collector 32, a cyclone separator 34, a collection jar 36, ablower 42, a sample velocity probe 44, a system velocity probe 46 and amanometer 48. Sample collector 32 is positioned at the point to bemeasured such that the plane of the inlet is positioned perpendicular tothe direction of the sample point air flow. The drift sample whichenters collector 32 is directed into cyclone separator 34 where theentering liquid and solid particles are separated from the exhaust airby centrifugal force and collected in collection jar 36. In order toinsure that the drift particles which enter collector 32 are trulyrepresentative of those entrained in the exhaust air at the samplingpoint, the velocity at thecollector inlet must be maintained close tothe natural velocity of the cooling tower exhaust air to avoid particlediscrimination. The adjustment to this isokinetic condition is attainedby varying the speed of the centrifugal blower 42 until the totalpressure measured adjacent the collector inlet by probe 44 and the totalpressure measured at the blower discharge by probe 46 are in balance.Any imbalance is detected by manometer 48.

Referring to FIGS. 2 and 3, sample collection apparatus 30 includes ahollow sample collector member 32 having an inlet 33, a sample directingpassageway 35, and an outlet 37. Secured to outlet 37 of collector 34 isa tubular member 39 defining a passageway therethrough having a firstend 41 secured to and in communication with outlet 37 and a second end43 secured to and in communication with cyclone separator 34. Cycloneseparator 34 is of conventional structure having an inner chamber 45where the particles of the exhaust air-drift mixture are centrifugallyforced to the separator walls causing them to flow downward into acollection jar 36 secured to and in communication with the bottom ofchamber 45. A flexible conduit 47 has a first end 49 secured to and incommunication with the upper end of chamber 45 and a second end 51secured to the inlet of blower 42. Blower 42 is effective to draw theexhaust air from chamber 45 through conduit 47 into blower 42 and thento atmosphere through blower outlet 53, as indicated by arrows in FIG.2.

Referring to FIGS. 2, 3 and 5, isokinetic control apparatus 40 includesa pair of velocity measuring probes 44 and 46, an inclined manometer 48and a variable speed blower control assembly 55. Probe 44 is positionedadjacent inlet 33 of collector 32 and vertically extends downwardparallel to the direction of exhaust air flow, indicated by arrows inFIG. 2, to measure total pressure adjacent inlet 33. Probe 44 is securedto collector 32 to permit movement therewith by rod 56, connected at itsopposite ends respectively thereto. Probe 44 is of the conventionaltotal pressure type and includes pressure transmission tubing 57 havinga first end 58 secured to probe 44 and a second end 59 secured to afirst end 60 of manometer 48. A second total pressure probe 46 ispositioned at blower outlet 53 in facing relationship thereto to measurethe total pressure at the blower discharge. Transmission tubing 64 has afirst end 65 secured to probe 46 and a second end 66 secured to a secondend 62 of manometer 48. Inclined manometer 48 is calibrated to comparethe total pressure at inlet 33 measured by probe 44 to the totalpressure at blower outlet 53 measured by probe 46.

A variable speed blower control assembly 55 of conventional constructionis provided to vary the speed of centrifugal blower 42 and therebycontrol the velocity through the system. The inlet 33 and outlet 53 aredesigned to have substantially equal areas so that when manometer 48indicates that the total pressures measured by probes 44 and 46 are inbalance the velocity at collector inlet 33 is equal to the naturalvelocity of the cooling tower exhaust air. This isokinetic conditioninsures that the drift particles which enter the drift measurementsystem are truly representative of those entrained in the exhaust air atthe sampling point.

In order to accurately represent the total average drift emitted from acooling tower it is necessary to collect drift samples from variouspre-selected points at the fan stack discharge. To facilitate such atest procedure it is necessary that sample collection apparatus 30 beable to traverse the fan stack. To this end, a monorail apparatus 50 isprovided including a monorail 70, of square cross section, whichtraverses fan stack 10. Mono-rail 70 receives a tubular member 72slideable thereon, which is suitably secured to collector 32 and cycloneseparator 34. A conventional pulley system 74 is provided to controlback and forth movement of member 72 and collection apparatus 30attached thereto, from one side of fan stack 10.

It is also important that the plane of collector inlet 33 be positionedperpendicular to the direction of the sample point air flow. To thisend, it is necessary to mount mono-rail 70 to fan stack 10 in a mannerwhich permits rotation thereof about a horizontal axis and to providemeans to indicate when the plane of collector inlet 33 is perpendicularto the direction of exhaust air flow. Additionally, since driftmeasurement system 20 will be employed to operate on fan stacks ofdifferent diameters it is necessary that the mounting means accommodatesuch adjustment. Referring to FIGS- l and 5, the respective square ends73 and 76 of mono-rail 70 are received respectively by circular collars76 and 77. End 73 is slideably received within collar 75 which in turnis rotatably secured to a flange 78, selectively clamped to the fanstack wall in a conventional manner. End 76 is rigidly secured to collar77 which is rotatably secured within housing 80 of control apparatus 30.Housing 80 is selectively clamped to the fan stack wall in a suitablemanner. Rotating means as indicated at 85, of conventional construction,is secured to end 76 and housing 80 to permit selective rotation andlocking of mono-rail 70 and collars 75 and 77 relative thereto. Rotatingmeans includes a rod having an upper portion 96 secured to end 76 ofmono-rail 70 by U-clamp 97 and a lower portion 98 having a followermember 99 secured thereto. Follower member 99 is re- 102 secured tohousing 80. Rotation of rod 95 results in rotation of mono-rail 70 andmovement of follower 99 within slot 100. Follower 99 includes aconventional locking nut arrangement (not shown) to selectively lockfollower 99 in position within slot 100. As best seen in FIGS. 1 and 3,a direction vane 82 is pivotally secured to probe 44 about asubstantially horizontal axis. Direction vane 82 includes a rod 83pivotally secured to probe 44 at one end and secured to a plate 84 atthe other end. The exhaust air from fan stack contacting plate 84 causesrod 83 to pivot relative to probe 44 until it reaches an equilibriumposition, as seen in FIG. 1. Since the vertical portion of probe 44extends perpendicular to the plane of inlet 33, the air flow directionat the sample point will be perpendicular to said plane when rod 83 isin longitudinal alignment with said vertical portion of probe 44. Themono-rail 70 is rotated until such condition is achieved and then lockedin place.

Referring to FIG. 4, collecting jar 36 is threadedly received by aconnecting flange 86 secured to the bottom of cyclone separator chamber45. Mounted within jar 36 is a funnel shaped member 88 having wallswhich converge downwardly and inwardly from the top of jar 36 towardsthe bottom thereof. Extending through member 88 is a hollow tube 90,having a first end 92 positioned within cyclone separator chamber 45 anda second end 94 positioned adjacent the bottom of collection jar 36.Member 88 and tube 90 are effective to minimize evaporation of thecollected sample by equalizing the pressure between chamber 45 and jar36 and eliminating the swirl component of the collected sampie.

The hereinbelow described testing procedure is by way of example, asmany other testing procedures may be employed to collect drift samplesin accordance with the present invention which will accurately representthe total average drift emitted from a cooling tower. The area of thefan stack discharge is divided into five concentric equal area annuli.Drift samples are collected at the center radius of each of these annuliin all four quadrants yielding samples. Sample collection apparatus ispositioned at each center radius and positioned such that the planepassing through inlet 33 is perpendicular to the direction of theexhaust air flow. Control apparatus 40 is likewise adjusted at eachcenter radius until isokinetic sampling conditions are achieved. Arepresentative isokinetic sample is allowed to flow through the systemand be collected in jar 36 for a predetermined time period; usually from10 to 20 minutes per sample point. The total drift sample collected ismeasured and chemically analyzed to determine the dissolved solidcontent. With the total sample quantity, chemical composition, andsample time known, the weighted average drift emission rate can beevaluated and conveniently calibrated to the flow rate and chemicalcomposition of the water circulating in the cooling tower system.

The hereinabove described method and apparatus is a simple, direct andhighly accurate procedure for quantitatively measuring cooling towerdrift in the field. It should be understood, of course, that theforegoing disclosure relates to only a preferred embodiment of theinvention and that numerous modifications or alterations may be madetherein without departing from the spirit and the scope of the inventionas set forth in the appended claims.

What is claimed:

1. Apparatus for quantitatively measuring the drift emitted from the fanstack of a cooling tower, comprising:

a. sample collecting means positioned for collecting a test sample froma point in the fan stack exhaust air;

b. isokinetic sampling control means in communication with said samplecollecting means for establishing the velocity of said collected testsample at substantially equal to the natural velocity of the exhaustair;

c. cyclone separator means for separating the liquid or solid particlesfrom said test sample, said cyclone separator means includingcentrifugal blower means having a blower discharge outlet associatedtherewith;

d. said isokinetic sampling control having a first total pressuremeasuring probe positioned adjacent said sample collecting means withinthe exhaust air and a second total pressure measuring probe positionedadjacent said blower discharge outlet so as to permit control of saidblower for balancing the total pressure of the exhaust air at saidsampling point with the total pressure at said blower discharge outlet;and

e. container means for'receiving said separated liquid or solidparticles.

2. Apparatus in accordance with claim I wherein said isokinetic samplingcontrol means further includes manometer means associated with saidfirst and second probes to detect imbalance between the total pressuresmeasured by said first and second probes.

3. Apparatus in accordance with claim 2 wherein said blower meansincludes speed control means for varying the speed of said blower meansand thereby balancing the total pressures measured by said first andsecond probes.

4. Apparatus for quantitatively measuring the drift emitted from the fanstack of a cooling tower, comprising:

a. sample collecting means positioned for collecting a test sample froma point in the fan stack exhaust air, said sample collecting meansincluding a hollow sample collecting member having an inlet openingassociated therewith, a direction vane means is provided to indicatewhen the plane passing through said inlet opening is perpendicular tothe direction of the sample point air flow;

b. isokinetic sampling control means in communication with said samplecollecting means for establishing the velocity of said collected testsample at substantially equal to the natural velocity of the exhaustair;

0. cyclone separator means for separating the liquid or solid particlesfrom said test sample; and

d. container means for receiving said separated liquid or solidparticles.

5. Apparatus in accordance with claim 4 wherein said sample collectingmember may be rotated about a substantially horizontal axis so as topermit rotation of said inlet opening until said plane passingtherethrough is perpendicular to the direction of the sample point airflow.

6. Apparatus for quantitatively measuring the drift emitted from the fanstock of a cooling tower, comprismg:

a. sample collecting means positioned for collecting a test sample from.a point in the fan stack exhaust air;

b. isokinetic sampling control means in communication with said samplecollecting means for establishing the velocity of said collected testsample at substantially equal to the natural velocity of the exhaustair;

c. cyclone separator means for separating the liquid or solid particlesfrom said test sample;

d. said sample collecting means and said cyclone separator means beingpositioned upon mono-rail means which extends across said fan stack in amanner which permits them to traverse said fan stack and be selectivelypositioned therealong; and

e. container means for receiving said separated liquid or solidparticles.

7. Apparatus in accordance with claim 6 wherein said sample collectingmeans includes a hollow sample collecting member having an inlet openingassociated therewith, and said mono-rail means being rotatable about asubstantially horizontal axis so as to permit positioning of the planepassing through said inlet opening perpendicular to the direction of thesample point air flow.

8. Apparatus in accordance with claim 7 wherein the respective ends ofsaid mono-rail means are releasably secured to said fan stack byconnecting means which permits adjustment of the length of saidmono-rails means to accommodate fan stacks of varying diameters.

9. Apparatus in accordance with claim 6 wherein said container meansincludes a funnel shaped member positioned therein, said member havingan upwardly extending tube passing the'rethrough such that the upper endthereof extends into said cyclone separator means and the lower endthereof extends below said member into said container means, so as tominimize evaporation of said received particles.

10. Apparatus for quantitatively measuring the drift emitted from thefan stack of a cooling tower, comprismg: i

a. sample collecting means positioned for collecting a test sample froma point in the fan stack exhaust air;

b. isokinetic sampling control means in communication with said samplecollecting means for establishing the velocity of said collected testsample at substantially equal to the natural velocity of the exhaustair;

c. cyclone separator means for separating the liquid or solid particlesfrom said test sample; and

d. container means secured to said cyclone separator means immediatelytherebelow and in fluid communication therewith for receiving thedownward flow of said separated liquid or solid particles.

11. Apparatus for quantitatively measuring the drift emitted from thefan stack of a cooling tower, comprising:

a. sample collecting means positioned for collecting a test sample froma point in the fan stack exhaust air, said sample collecting meansincluding a hollow sample collecting member having an inlet openingassociated therewith, said inlet-opening being positioned such that aplane passing therethrough is perpendicular to the direction of thesample point exhaust air flow;

b. isokinetic sampling control means in communica tion with said samplecollecting means for establishing that the velocity of said collectedtest sample is substantially equal to the natural velocity of the samplepoint exhaust air;

c. cyclone separator means for separating the liquid or solid particlesfrom said test sample, said cyclone separator means includingcentrifugal blower means having a'blower discharge outlet associatedtherewith;

d. said isokinetic sampling control means including a first totalpressure measuring probe positioned adjacent said sample collectingmember inlet and a second total pressure measuring probe positionedadjacent said blower discharge outlet, said first and second probeshaving manometer means associated therewith to detect imbalance betweenthe total pressures measured thereby;

e. speed control means associated with said blower means for varying thespeed of said blower means and to balance the total pressures measuredby said first and second probes;

f. direction vane means associated with said sample collecting memberfor indicating when said plane passing through said inlet opening isperpendicular to the direction of sample point air flow; and

g. container means associated with said cyclone separator means forreceiving said separated liquid or solid particles.

1. Apparatus for quantitatively measuring the drift emitted from the fanstack of a cooling tower, comprising: a. sample collecting meanspositioned for collecting a test sample from a point in the fan stackexhaust air; b. isokinetic sampling control means in communication withsaid sample collecting means for establishing the velocity of saidcollected test sample at substantially equal to the natural velocity ofthe exhaust air; c. cyclone separator means for separating the liquid orsolid particles from said test sample, said cyclone separator meansincluding centrifugal blower means having a blower discharge outletassociated therewith; d. said isokinetic sampling control having a firsttotal pressure measuring probe positioned adjacent said samplecollecting means within the exhaust air and a second total pressuremeasuring probe positioned adjacent said blower discharge outlet so asto permit control of said blower for balancing the total pressure of theexhaust air at said sampling point with the total pressure at saidblower discharge outlet; and e. container means for receiving saidseparated liquid or solid particles.
 2. Apparatus in accordance withclaim 1 wherein said isokinetic sampling control means further includesmanometer means associated with said first and second probes to detectimbalance between the total pressures measured by said first and secondprobes.
 3. Apparatus in accordance with claim 2 wherein said blowermeans includes speed control means for varying the speed of said blowermeans and thereby balancing the total pressures measured by said firstand second probes.
 4. Apparatus for quantitatively measuring the driftemitted from the fan stack of a cooling tower, comprising: a. samplecoLlecting means positioned for collecting a test sample from a point inthe fan stack exhaust air, said sample collecting means including ahollow sample collecting member having an inlet opening associatedtherewith, a direction vane means is provided to indicate when the planepassing through said inlet opening is perpendicular to the direction ofthe sample point air flow; b. isokinetic sampling control means incommunication with said sample collecting means for establishing thevelocity of said collected test sample at substantially equal to thenatural velocity of the exhaust air; c. cyclone separator means forseparating the liquid or solid particles from said test sample; and d.container means for receiving said separated liquid or solid particles.5. Apparatus in accordance with claim 4 wherein said sample collectingmember may be rotated about a substantially horizontal axis so as topermit rotation of said inlet opening until said plane passingtherethrough is perpendicular to the direction of the sample point airflow.
 6. Apparatus for quantitatively measuring the drift emitted fromthe fan stock of a cooling tower, comprising: a. sample collecting meanspositioned for collecting a test sample from a point in the fan stackexhaust air; b. isokinetic sampling control means in communication withsaid sample collecting means for establishing the velocity of saidcollected test sample at substantially equal to the natural velocity ofthe exhaust air; c. cyclone separator means for separating the liquid orsolid particles from said test sample; d. said sample collecting meansand said cyclone separator means being positioned upon mono-rail meanswhich extends across said fan stack in a manner which permits them totraverse said fan stack and be selectively positioned therealong; and e.container means for receiving said separated liquid or solid particles.7. Apparatus in accordance with claim 6 wherein said sample collectingmeans includes a hollow sample collecting member having an inlet openingassociated therewith, and said mono-rail means being rotatable about asubstantially horizontal axis so as to permit positioning of the planepassing through said inlet opening perpendicular to the direction of thesample point air flow.
 8. Apparatus in accordance with claim 7 whereinthe respective ends of said mono-rail means are releasably secured tosaid fan stack by connecting means which permits adjustment of thelength of said mono-rails means to accommodate fan stacks of varyingdiameters.
 9. Apparatus in accordance with claim 6 wherein saidcontainer means includes a funnel shaped member positioned therein, saidmember having an upwardly extending tube passing therethrough such thatthe upper end thereof extends into said cyclone separator means and thelower end thereof extends below said member into said container means,so as to minimize evaporation of said received particles.
 10. Apparatusfor quantitatively measuring the drift emitted from the fan stack of acooling tower, comprising: a. sample collecting means positioned forcollecting a test sample from a point in the fan stack exhaust air; b.isokinetic sampling control means in communication with said samplecollecting means for establishing the velocity of said collected testsample at substantially equal to the natural velocity of the exhaustair; c. cyclone separator means for separating the liquid or solidparticles from said test sample; and d. container means secured to saidcyclone separator means immediately therebelow and in fluidcommunication therewith for receiving the downward flow of saidseparated liquid or solid particles.
 11. Apparatus for quantitativelymeasuring the drift emitted from the fan stack of a cooling tower,comprising: a. sample collecting means positioned for collecting a testsample from a point in the fan stack exhaust air, said sample collectingmeans including a hollow sample collecting mEmber having an inletopening associated therewith, said inlet opening being positioned suchthat a plane passing therethrough is perpendicular to the direction ofthe sample point exhaust air flow; b. isokinetic sampling control meansin communication with said sample collecting means for establishing thatthe velocity of said collected test sample is substantially equal to thenatural velocity of the sample point exhaust air; c. cyclone separatormeans for separating the liquid or solid particles from said testsample, said cyclone separator means including centrifugal blower meanshaving a blower discharge outlet associated therewith; d. saidisokinetic sampling control means including a first total pressuremeasuring probe positioned adjacent said sample collecting member inletand a second total pressure measuring probe positioned adjacent saidblower discharge outlet, said first and second probes having manometermeans associated therewith to detect imbalance between the totalpressures measured thereby; e. speed control means associated with saidblower means for varying the speed of said blower means and to balancethe total pressures measured by said first and second probes; f.direction vane means associated with said sample collecting member forindicating when said plane passing through said inlet opening isperpendicular to the direction of sample point air flow; and g.container means associated with said cyclone separator means forreceiving said separated liquid or solid particles.